An apparatus and method for switching optical signal is disclosed. An optical
signal switch array includes a plurality of optical switches, each optical switch
having a first trench adapted to hold index-matching fluid, and a second trench
adapted to hold the index-matching fluid, but initially containing gas, the second
trench connected to said first trench. A first expansion chamber is connected to
the first trench, the first expansion chamber adapted to hold gas. A second expansion
chamber is connected to the second trench, the second expansion chamber adapted
to hold gas. To effect switching, the first expansion chamber is heated expanding
gas in the first expansion chamber, the expanding gas shifting the index-matching
fluid in the first trench to the second trench. Bistability is achieved by the
use of capillary action, which passively holds the droplet of working fluid in
either of two stable states until actuation.
